The online retailer is introducing a service that lets Twitter users add Amazon.com products to their carts without leaving the social media site.

The service comes as Amazon seeks to make social media a bigger source for sales. Twitter also has been seeking new revenue streams beyond advertising services like promoted tweets.

Under the program, users must link their Amazon.com account with their Twitter account. Then they need to add the hashtag #AmazonCart when replying to a tweet that has an Amazon product link. The product will then be automatically added to their shopping cart.

Twitter users will get a reply tweet from @MyAmazon as well as an email from Amazon when the item is successfully added to their cart.

The service is for U.S. customers only, although U.K. users have a similar service with the hashtag #AmazonBasket.

“This is an example of the constant innovation both Amazon and Twitter are using to push social shopping forward, but I don’t think it’s going to be a huge needle mover for either company,” said CRT Capital analyst Neil Doshi. “More and more people are showing items they’ve bought on Twitter, so it might be a way for followers to buy something more quickly.”

Shares in Seattle-based Amazon.com Inc. rose $1.63 to $309.64 in afternoon trading. Shares in Twitter Inc., which is based in San Francisco, rose 9 cents to $39.11.